The National Instruments PXI-8420/4 is a 4-port RS-232 serial interface card for PXI chassis that expands serial connectivity in test, measurement, and automation systems. It provides independent port configuration for baud rate, data bits, and parity, functioning as standard COM ports within Windows operating systems. The card connects to laboratory instruments, data acquisition devices, and industrial equipment via RS-232 serial protocol.
Technical Specifications
• Interface Type: RS-232
• Number of Ports: 4
• Bus Architecture: PXI
• UART Chipset: 16550-compatible
• Maximum Baud Rate: 115.2 kbps
• FIFO Buffer: 64 Bytes per port
• Connectors: 10-position modular jacks (optional DB-9 and DB-25 cable adapters available)
• Power Supply: +5 VDC at 125 mA typical / 200 mA maximum; ±12 VDC at 40 mA typical / 400 mA maximum
• Dimensions: 21.0 × 12.4 × 3.7 cm
• Isolation: Non-isolated
– Key Features
• Each RS-232 port independently configurable for protocol parameters
• Presents as standard Windows COM ports—no custom drivers required for basic serial I/O
• 64-byte FIFO buffers reduce CPU overhead during burst transfers
• Plug-and-Play installation within PXI systems
• Low power consumption suitable for chassis-integrated deployment
– Typical Applications
• Instrument control: oscilloscopes, multimeters, chromatographs, spectrometers
• Multi-device data acquisition from serial-enabled sensors and loggers
• Industrial automation and legacy equipment integration
• Laboratory environments requiring more than one or two serial ports
– Compatibility & Integration
• Operating Systems: Windows 2000, NT, XP, Me, 9x; LabVIEW Real-Time
• Software Frameworks: NI-VISA, NI-Serial; standard Windows NT serial communications API
• Development Environments: LabVIEW, LabWindows/CVI, Visual Basic, Visual C++, Measurement Studio, Excel, Lookout
• Driver Support: NI-Serial driver package
